Refractory metals gallium

Another type of ion gun produces positive ions from a liquid metal (almost always gallium) in the manner shown schematically in Fig. 3.2 [3.7]. A fine needle (f tip radius 5 pm) of refractory metal passes through a capillary tube (d) into a reservoir of liquid metal (e). The liquid is drawn up through the tube over the needle tip by capil-... 

It would appear from this patent literature that the development trends for PAFC cathode alloy electrocatalysts are from platinum, to Pt-refractory metal (vanadium) to Pt-Cr, to Pt-Cr-Co through to Pt-Fe-Co and then the various gallium additions to these combinations. It would seem, particularly in the case of gallium additions, that the gallium should induce porosity into the platinum alloys, since it would be expected to leach out easily. 

Trace determinations in different metal bases (e.g. lead, gallium and indium) can make use of pre-concentration based on a partial dissolution of the matrix (see Ref. [318]). Refractory metals such as molybdenum, niobium, tungsten and tantalum... 

Trace determinations in different metal bases (e.g., lead, gallium, and indium) can make use of pre-concentration based on a partial dissolution of the matrix (see Ref [367]). Refractory metals such as molybdenum, niobium, tungsten, and tantalum powders are definitely difficult to dissolve or to keep in solution and require trace matrix separations to achieve a reliable volatilization of the analytes, e.g. in graphite furnace AAS. Here, slurry sampling electrothermal AAS, as has been extensively investigated for these matrices by Krivan et al. (see, e.g.. Refs. [227, 343, 344]), is a worthwhile alternative, especially as contamination is prevented and calibration by addition of aqueous aliquots of the analytes is often possible. 

Of the 80 or so scarce elements, many occur in solid solution in major rock-forming minerals (e.g., rubidium, strontium, vanadium, germanium, gallium, scandium, rare earth elements (REEs)), or in solid solution in widely distributed, refractory, or low-solubility accessory phases (e.g., hafnium). Some elements, such as zirconium and phosphorus, form their own minerals. Others, like the base metals (e.g., copper, lead, zinc), semi-metals (arsenic, antimony, bismuth), and... 

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